Technical question re scrolls Options

[DavidW]

I think the next version of IA is meant to block scroll use on partly visible creatures.

I don't personally have a problem with that kind of scroll use, but that's a judgement call no doubt. I'm more curious about the technical side of things: how are you actually doing it? I can't offhand think of a good way, so that suggests there's a trick available here that I don't know about. (Of course, you could just add bulk Protection from XYZ to Improved Invisibility, but I'd guess it then won't behave properly under Truesight, so I assume there's something cleverer going on.)